In the last decade, there has been much research on topsheets that have an opening, which leads to a void space to receive or store BM. The focus has mainly been to reduce leakage from the diaper by improving the positioning of the opening against the wearer's body and in proximity of the anus of the wearer, for example by use of elastication means around the opening in the topsheet.
The inventors have found that the BM leakage problem is not only or not mainly caused by BM which is not received through the opening in the topsheet, but that an important part of the leakage problem is caused by BM which leaks back out of the storage space. The inventors have now found that the BM leakage problem of such diapers can be reduced when an additional topsheet (herein referred to as first topsheet) is provided underneath the topsheet with the opening, whereby the second topsheet traps the BM received through said opening.
In recent years, diaper manufacturers have done research on such diaper topsheets that can immobilize or trap BM, so that BM leakage from the diaper can be reduced. It has for example been suggested to incorporate in a diaper BM modifying agents, which for example change the viscosity of the BM material. Also suggested are, for example in WO99/56680 and EP-A-1057464, is the use of topsheets that comprise a backing material with thereon anchor portions with fibers that vertically extend from the backing layer and trap the BM. WO99/62446 and EP-A-1190690 describes loop-shaped fibers that are attached to such a backing sheet and which are said to trap BM material.
These suggested topsheet materials typically require a large volume (thickness) in order to store large quantities of BM and they are designed such that they can even store the BM under a certain pressure, e.g. when a baby is sitting. Subsequently, the suggested topsheets are typically thick and quite rough materials, which are thus not very comfortable. Furthermore, some of the topsheet materials suggested in the art are quite complex or difficult to produce, for example involving complex steps to anchor fibers to backing sheets. The use of these types of materials in diapers is thus not very economical.
There is thus still a need for diapers with an alternative BM trapping topsheet, which not only provides good BM trapping but which is also soft and comfortable in use.
The inventors have now found a diaper with such an alternative topsheet, which can be effectively used in diapers with a second topsheet with an opening, as described above. The topsheet has a supporting structure of regions where large fibers are bonded to one another and large regions (which do not contribute to the supporting structure) where the fibers are unbonded and extend in a loop-shape from the surface, and which trap the BM.
Because no backing sheet is needed as supporting structure, the tospheet is soft, thin, comfortable, and more economical. Diapers with this type of topsheet are found to have much less BM leakage and less BM deposition on the wearer's skin, whilst still being very soft and comfortable.